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Stephen T Sewell

Publications and source records attributed to Stephen T Sewell.

2 recordsLinked to original sources

Developmental patterning in the Caenorhabditis elegans hindgut.

Developmental pattern formation allows cells within a tissue or organ to coordinate their development and establish cell types in relationship to one another. To better characterize the developmental patterning events within one organ, the C. elegans hindgut, we have analyzed the expression pattern of several genes using green fluorescent protein-based reporter transgenes. In wild-type animals, these genes are expressed in subsets of hindgut cells rather than in individual cell types. In mutant animals, we find that some, but not all, genes expressed in cells with altered development exhibit a corresponding alteration of gene expression. The results are consistent with a model where a combination of factors contribute to each cell's fate, and address how developmental information converges to specify cell types.

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A targeted gain of function screen in the embryonic CNS of Drosophila.

In order to identify genes involved in the development of the central nervous system (CNS) we have undertaken a gain of function screen in the embryonic CNS of Drosophila. Transposable P-elements and the UAS/GAL4 system were used to initiate transcription of genes in a pan-neural pattern using scaGAL4. Over 4100 individual P-element insertion lines were screened with monoclonal antibodies BP102 and 1D4 to visualize axon pathways. Twenty-five P-element insertions corresponding to 18 genes resulted in aberrant CNS axon pathfinding when misexpressed with scaGAL4. Genes involved in axon guidance, embryonic patterning, and cell cycle regulation were isolated. In addition, we identified several zinc finger transcription factors not previously implicated in axon guidance or CNS development. This group includes Squeeze, Kruppel homolog-1, Hepatocyte nuclear factor 4, and two uncharacterized genes, CG11966 and CG9650. Calnexin99A, a putative molecular chaperone, was isolated as well.

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